The invention relates to piston and cylinder units and more particularly to such a unit whose cylinder tube, which contains an axially running piston driving a piston rod extending through a packing in at least one of two cylinder end caps mounted on the cylinder ends, is provided with trunnions so that after the unit has been mounted on some supporting structure it may be rocked about the trunnion axis which is perpendicular to the cylinder tube axis.
In all cases in which a part of a mechanical system, such as a machine part or the load carrying part of a tipper truck, has to be tilted or swung by a piston and cylinder unit, the piston and cylinder unit itself also has to be pivotally mounted, as for example by trunnions welded on the cylinder tube which are carried in bearings or the like. A disadvantage in this respect is that such welding operations may well lead to a deformation of the cylinder tube so that the piston will no longer run smoothly inside it. Furthermore, with such arrngements it is practically impossible to change the position of the pivot axis, although such a modification is frequently required, if the angle of pivot of the piston and cylinder unit is to be altered. The only remedy would then be to cut off the trunnions on the piston and cylinder unit and weld new ones on in a different position. This however tends to be highly inconvenient and it is often very difficult to so perfectly align the trunnions that they have a true fit in the bearings already existing in the arrangement.